Structure and property of multicomponent germanate glass containing Y2O3

Abstract

CaO–BaO–Al₂O₃–SiO₂–GeO₂ glasses doped with 0·00–16·67 wt-% Y₂O₃ have been prepared by conventional melt quenching method. The influence of Y₂O₃ addition on the properties and structure of the glasses has been investigated. The results show that, with the introducing of Y₂O₃, the density, glass transition temperature and thermal expansion coefficient of the glass increase but the chemical durability declines. In addition, compared with the glass without Y₂O₃, the bend strength of the glass including 4·76 wt-% Y₂O₃ increased from 54 to 110 Mpa. The possible mechanism is that yttria acts as a network former in the structure and makes the island shape network unit repolymerisation by forming Ge–O–Y bond. The absorption strength caused by hydroxyl vibration decreased up to completely disappearance as the Y₂O₃ content increased continuously. The introducing of yttria in the composition causes the conversion from four coordination to higher coordination germanium, which decreases non-bridge oxygen (NBO) and weakens hydroxyl characteristic absorption.     

Understanding the structure,thermal, and optical properties in Al2O3-incorporated La2O3-TiO2-Nb2O5 glasses

Glasses in the 30La₂O₃-40TiO₂-30Nb₂O₅ system are known to have excellent optical properties such as refractive indices over 2.25 and wide transmittance within the visible to mid-infrared (MIR) region. However, titanoniobate glasses also tend to crystallize easily, significantly limiting their applications in optical glasses due to processing challenges. Therefore, the 30La₂O₃-40TiO₂-(30−x) Nb₂O₅-xAl₂O₃ (LTNA) glass system was successfully synthesized using a aerodynamic containerless technique, which improves glass thermal stability and expands the glass-forming region. The effects of Al₂O₃ on the structure, thermal, and optical properties of base composition glasses were investigated by XRD, DSC, NMR, Raman spectroscopy, and optical measurements. DSC results indicated that as the content of Al₂O₃ increased, the thermal stability of the glasses and glass-forming ability increased, as the 30La₂O₃-40TiO₂-25Nb₂O₅-5Al₂O₃ (Nb-Al-5) glass obtained the highest ΔT value (103.5°C). Structural analysis indicates that the proportion of [AlO₄] units increases gradually and participates in the glass network structure to increase connectivity, promoting more oxygen to become bridging oxygen and form [AlO₄] tetrahedral linkages to [TiO₅] and [NbO₆] groups. The refractive index values of amorphous glasses remained above 2.1 upon Al₂O₃ substitution, and a transmittance exceeding 65% in the visible and mid-infrared range. The crystallization activation energies of 30La₂O₃-40TiO₂-30Nb₂O₅ (Nb-Al-0) and Nb-Al-5 glasses were calculated to be 611.7 and 561.4 kJ/mol, and the Avrami parameters are 5.28 and 4.96, respectively. These results are useful to design new optical glass with good thermal stability, high refractive index and low wavelength dispersion for optical applications such as lenses, endoscopes, mini size lasers, and optical couplers.     

Preparation and application evaluation of La2O3-doped Y2O3 crucible materials for melting TiAl alloys

A new La₂O₃-doped Y₂O₃ crucible materials was fabricated and evaluated by TiAl alloys melting test. Microstructure and properties of the La₂O₃-doped Y₂O₃ ceramics were systemically investigated. In addition, interfacial reaction mechanism of the La₂O₃-doped Y₂O₃ crucible materials and TiAl alloys, together with oxygen content of TiAl alloys were discussed. Solid solution of La³⁺ in the crystal lattice of Y₂O₃ significantly improved sintering properties of the La₂O₃-doped Y₂O₃ crucible materials and decreased the open porosity. Compared with pure Y₂O₃, when adding 15 wt% La₂O₃, the open porosity and strength retention ration after thermal shock test of the La₂O₃-doped Y₂O₃ crucible materials changed from 10.8% to 3.9% and from 64% to 78%, respectively. The interfacial reaction between La₂O₃-doped Y₂O₃ crucible materials and TiAl alloys belongs to physical dissolution, and no reaction products were found during the melting of TiAl alloys. When using the 15 wt% La₂O₃-doped Y₂O₃ crucible materials to melt TiAl alloys, oxygen content of the TiAl ingot declined to 530 ppm, which was only one fourth of that using pure Y₂O₃ materials.     

CaO–SiO2–Al2O3–Y2O3 glasses as model grain boundary phases for Si3N4 ceramics

The glasses with compositions derived from the eutectic composition [37.78 (Y₃Al₅O₁₂)·62.22 (SiO₂)] of the quasi-binary glass system (Y₃Al₅O₁₂)-(SiO₂) with addition of up to 20 mol.% CaO were investigated as model grain boundary phases for Si₃N₄ ceramics. The influence of CaO as model impurity on the physical properties of the glass (density, thermal expansion) and on the crystallisation behaviour was studied. Although the initial composition of the basic glass was that of yttrium-aluminium garnet (Y₃Al₅O₁₂–YAG), no crystalline YAG was detected. Apart from yttrium disilicate (Y₂Si₂O₇), anorthite (CaAl₂Si₂O₈), tricalcium aluminate (Ca₃Al₂O₆), and calcium yttrium oxide silicate (Ca₄Y₆O(SiO₄)₆), a new phase was detected, not found in the powder diffraction file (PDF) database. Cavities were formed within the devitrified glass due to the volume contraction after crystallisation. Possible implications for the mechanical properties of Si₃N₄ ceramics sintered with addition of Y₂O₃–Al₂O₃ are discussed in terms of the observed compositional dependences of the physical properties of CaO–Y₂O₃–Al₂O₃–SiO₂ glasses.     

Effect of Ta2O5 Substituting on Thermal and Optical Properties of High Refractive Index La2O3–Nb2O5 Glass System Prepared by Aerodynamic Levitation Method

High refractive index glasses with nominal composition of 0.35La₂O₃–(0.65?x)Nb₂O₅–xTa₂O₅ (x ≤ 0.35) were prepared by aerodynamic levitation method. The effect of Ta₂O₅ substituting on their thermal and optical properties was investigated. All the glasses obtained were colorless and transparent. Differential thermal analyzer results show that as the content of Ta₂O₅ increased, the thermal stability of the glasses increased but the glass‐forming ability decreased. The transmittance spectra of all the obtained glasses exhibited a wide transmittance window ranging from 380 to 5500 nm. As the content of Ta₂O₅ increased, the refractive index of the glasses was enhanced from 2.15 to 2.21 and the dispersion was reduced with the Abbe number increasing from 20 to 27.     

Anisotropic properties of textured h-BN matrix ceramics prepared using 3Y2O3-5Al2O3(-4MgO) as sintering additives

Textured hexagonal boron nitride (h-BN) matrix composite ceramics were prepared by hot pressing using 3Y₂O₃-5Al₂O₃ (mole ratio of 3:5) and 3Y₂O₃-5Al₂O₃-4MgO (mole ratio of 3:5:4) as liquid phase sintering additives, respectively. During the sintering process with liquid phase environments, platelike h-BN grains were rotated to be perpendicular to the sintering pressure, forming the preferred orientation with the c-axis parallel to the sintering pressure. Both h-BN matrix ceramic specimens show significant texture microstructures and anisotropic mechanical and thermal properties. The h-BN matrix ceramics prepared with 3Y₂O₃-5Al₂O₃-4MgO possess higher texture degree and better mechanical properties. While the anisotropy of thermal conductivities of that prepared with 3Y₂O₃-5Al₂O₃ is more significant. The phase compositions and degree of grain orientation are the key factors that affect their anisotropic properties.     

Thermal and optical properties of La2O3–Ga2O3– (Nb2O5 or Ta2O5) ternary glasses

La₂O₃–Ga₂O₃–M₂O₅ (M = Nb or Ta) ternary glasses were fabricated using an aerodynamic levitation technique, and their glass‐forming regions and thermal and optical properties were investigated. Incorporation of adequate amounts of Nb₂O₅ and Ta₂O₅ drastically improved the thermal stabilities of the glasses against crystallization. Optical transmittance measurements revealed that all the glasses were transparent over a wide wavelength range from the ultraviolet to the mid‐infrared. The refractive indices of the glasses increased and the Abbe number decreased upon substituting Ga₂O₃ with Nb₂O₅, and the decrease in the Abbe number was significantly suppressed when Ta₂O₅ was incorporated into the glass. As a result, excellent compatibility between high refractive index and lower wavelength dispersion was realized in La₂O₃–Ga₂O₃–Ta₂O₅ glasses. Analysis based on the single‐oscillator Drude–Voigt model provided more systematical information and revealed that this compatibility was due to an increase in the electron density of the glass.     

Synthesis and characterization of low CTE value La2O3-B2O3-CaO-P2O5 glass/cordierite composites for LTCC application

Low-softening-point La₂O₃-B₂O₃-CaO-P₂O₅ (LBCP) glass-ceramic/cordierite composite systems have been prepared in this work. Influence of the ratio of La₂O₃ to B₂O₃ and the content of cordierite on the sintering behavior, microstructure, sintering quality, thermal properties and dielectric properties of composites are studied. The results show that high La₂O₃/B₂O₃ ratio improves the crystalline quality of LBCP glass-ceramic, but also narrows its process window. The increase of cordierite content reduces the coefficient of thermal expansion (CTE) value of composites obviously. However, excess cordierite is detrimental to the densification of the composite microstructure, and too low cordierite content causes serious foaming. Sample containing 30?wt% LBCP1 glass-ceramic and 70?wt% cordierite sintered at 850?°C shows excellent properties: relative density of 95.26%, CTE value of 4.12?ppm/°C, dielectric constant of 4.78 (1?MHz)/4.52 (12.8?GHz), dielectric loss of 2.3?×?10^?3 (1?MHz)/2.5?×?10^?3 (12.8?GHz) and the ability to co-fire with silver, which suggests that LBCP glass/cordierite composite system has potential to meet the requirements of LTCC substrate material.     

Mid‐IR transparent TeO2‐TiO2‐La2O3 glass and its crystallization behavior for photonic applications

In this report, effect of enhanced rare earth (La₂O₃) concentration on substitution of TeO₂ within ternary TeO₂‐TiO₂‐La₂O₃ (TTL) glass system has been studied with respect to its thermal, structural, mechanical, optical, and crystallization properties with an aim to achieve glass and glass‐ceramics having rare‐earth‐rich crystalline phase for nonlinear optical and infrared photonic applications. DSC analysis (10°C/min) demonstrates a progressive increase in glass‐transition temperature (T_g) from 359 to 452°C with the increase in La₂O₃ content. Continuous glass network modification with transformation of [TeO₄] to [TeO₃/TeO₃₊₁] units is evidenced from Raman spectra which is corroborated with XPS studies. While mechanical properties demonstrate enhancement of cross‐linking density in the network. These glasses exhibit optical transmission window extended from 0.4 to 6 μm with calculated zero dispersion wavelength (λ_ZDW) varying from 2.41 to 2.28 μm depending upon La₂O₃ content. Crystallization kinetics of TTL10 (80TeO₂‐10TiO₂‐10La₂O₃ in mol%) glass has been studied via established models. Activation energy (E_a) has been evaluated and dimensionality of crystal growth (m) suggests formation of surface crystals. Glass‐ceramic with crystalline phase of La₂Te₆O₁₅ has been realized in heat‐treated TTL10 glass samples (at 450°C). As predicted from DSC analysis, FESEM study unveils the formation of surface crystallized glass‐ceramics.     

Enhanced mechanical and thermal properties of AlN ceramics via a chemical precipitation process

A uniform dispersion of sintering additives is crucial to improve the thermal and mechanical properties of AlN ceramics. In this study, the Y₂O₃-coated AlN composite powder was successfully prepared by the chemical precipitation (CP) process, thereby improving the homogenization of Y₂O₃ in AlN green compacts. The precipitation coating behavior of Y₂O₃ precursor was investigated by FTIR and TG-DSC, and the corresponding reaction equation was proposed. The results of TEM, XRD, and XPS for the CP processed AlN powder indicated that a uniform amorphous Y₂O₃ layer was fully wrapped on the surface of AlN powder. The microstructures and phases of the sintered AlN samples prepared via the CP and conventional ball-milling (BM) processes, respectively, were compared. The CP process can result in decreasing oxygen content in AlN grains, facilitating the formation of the desirable isolated second phases, and strengthening the grain and grain boundary of AlN ceramic. As a result, the thermal conductivity, bending strength and fracture toughness of the CP processed AlN ceramic are 9.43%, 10.56%, and 18.50% higher than those of the BM processed sample, respectively, illustrating the CP process is a pretty effective way to simultaneously improve the thermal and mechanical properties of AlN ceramics.     

Structure and crystallization behaviour of some MgSiO3-based glasses

We report on the structure and crystallization behaviour of four enstatite based glasses. Two glasses with nominal compositions of Y_0.125Mg_0.875Si_0.875B_0.125O₃ and Y_0.125Mg_0.725Ba_0.15Si_0.875B_0.125O₃ were prepared as parent glasses while the other two glasses were derived by the addition of 8 wt.% Al₂O₃ to the parent glass compositions, respectively. Structural features of the glasses were accessed by Fourier transform infrared spectroscopy (FTIR). Non-isothermal crystallization kinetics and thermal stability of Al₂O₃-free glasses were studied using differential scanning calorimetry (DSC). It has been shown that these glasses exhibit higher activation energy of viscous flow and are prone to surface crystallization. Activation energy of crystallization decreases with the addition of BaO in the glasses. Crystallization behaviour of all the experimental glasses in the temperature range of 800–1000 °C was followed by X-ray diffraction (XRD) and FTIR. Clinoenstatite and orthoenstatite were the major crystalline phases in the BaO-free glass-ceramics while BaO-containing compositions featured the early formation and stabilization of protoenstatite.     

Thermal Stability,Optical Transmittance,and Refractive Index Dispersion of La2O3–Nb2O5–Al2O3 Glasses

La₂O₃–Nb₂O₅–Al₂O₃ high‐refractive‐index glasses were fabricated by containerless processing, and the glass‐forming region was determined. The thermal stability, density, optical transmittance, and the refractive index dispersion of these glasses were investigated. All the glasses were colorless and transparent in the visible to near infrared (NIR) region and had high refractive index with low wavelength dispersion. Some of these glasses were found to have significantly high glass‐forming ability. These results indicate that the ternary glasses are suitable for optical applications in the visible to NIR region. The effects of the substitution of Al₂O₃ for Nb₂O₅ on optical properties were discussed on the basis of the Drude–Voigt equation. It was suggested that the substitution of Al₂O₃ for Nb₂O₅ increased the molecular density and suppressed a decrease in the refractive index, even when both the average oscillator strength and inherent absorption wavelength decreased in La₂O₃–Nb₂O₅–Al₂O₃ glasses. These results are helpful for designing new optical glasses controlled to have a higher refractive index and lower wavelength dispersion.     

Highly transparent Yb:Y2O3 ceramics obtained by solid-state reaction and combined sintering procedures

(Y_0.87-xLa_0.1Zr_0.03Yb_x)₂O₃ (x?=?0.02, 0.04, 0.05) transparent ceramics were obtained by solid-state reaction and combined sintering procedures with La₂O₃ and ZrO₂ as sintering additives. A method based on two-step intermediate sintering in air followed by vacuum sintering was applied in order to control the densification and grain growth of the samples during the final sintering process. The results indicate that La₂O₃ and ZrO₂ co-additives can improve the microstructure and optical properties of Yb:Y₂O₃ ceramics at relatively low sintering temperature. On the other hand, the addition of Zr⁴⁺ ions leads to the formation of dispersed scattering volumes in the ceramic bodies. Transmittance of 78.8% was measured for the 2.0?at% Yb:Y₂O₃ ceramic sample at the wavelength of 1100?nm. The spectroscopic properties of Yb:Y₂O₃ ceramics were investigated at room temperature. The obtained results show that the absorption cross-section at 978?nm is in the range of 2.08?×?10^–20 to 2.36?×?10^–20 cm², whereas the emission cross-section at 1032?nm is ~1.0?×?10^–20 cm².     

Fabrication and characterization of highly transparent Er:Y2O3 ceramics with ZrO2 and La2O3 additives

In this study, we report highly transparent Er:Y₂O₃ ceramics (0–10 at% Er) fabricated by a vacuum sintering method using compound sintering additives of ZrO₂ and La₂O₃. The transmittance, microstructure, thermal conductivity and mechanical properties of the Er:Y₂O₃ ceramics were evaluated. The in-line transmittance of all of the Er:Y₂O₃ ceramics (1.2 mm thick) exceeds 83% at 1100 nm and 81% at 600 nm. With an increase in the Er doping concentration from 0 to 10 at%, the average grain size, microhardness and fracture toughness remain nearly unchanged, while the thermal conductivity decreases slightly from 5.55 to 4.89 W/m K. A nearly homogeneous doping level of the laser activator Er up to 10 at% in macro-and nanoscale was measured along the radial direction from the center to the edge of a disk specimen, which is the prominent advantage of polycrystalline over single-crystal materials. Based on the finding of excellent optical and mechanical properties, the compound sintering additives of ZrO₂ and La₂O₃ are demonstrated to be effective for the fabrication of transparent Y₂O₃ ceramics. These results may provide a guideline for the application of transparent Er:Y₂O₃ laser ceramics.     

Structural, optical and bioactive properties of calcium borosilicate glasses

Glass of composition 40SiO₂–20B₂O₃–30CaO–10M₂O₃ (M = Al, Cr, Y and La) were prepared by the splat quenching technique to investigate the effect of M₂O₃ on their bioactivity, structural and optical properties. Y₂O₃ and Cr₂O₃ containing glasses formed a crystalline hydroxyapatite (HA) layer after dipping in simulating body fluid (SBF) for 25 days. On the other hand, HA layer could not form in Al₂O₃ and La₂O₃ glasses. However, during soaking in SBF solution, these glasses exhibit higher dissolution rate, lower density and increased optical band gap as compared to unsoaked glasses. Their oxygen molar volume was also higher than for Y₂O₃ and Cr₂O₃ glasses. The change in composition affects the cross-link formation in the glass matrix and finally its durability and bioactivity in SBF. The results show that M₂O₃ plays an important role in controlling chemical durability and bioactivity of the glasses.     

Effect of Y2O3 on the structural,optical and radiation shielding properties of transparent Na-rich borate glass with diluted and fixed Fe2O3

We study the impact of yttrium oxide (Y₂O₃) on the optical properties of iron-doped borate glasses. A series of borate glasses, with a diluted and constant amount of Fe₂O₃, doped with various amounts of Y₂O₃ (labeled as BNaFeY-glasses) was prepared and studied. The impact of Y₂O₃ doping on the optical transitions of BNaFeY-glasses was studied by analyzing the optical absorption spectra. The presence of Fe cations, with their Fe³⁺ state, leads to the appearance of absorption in the ultraviolet region. Furthermore, the optical transmittance spectra proved the transparency of all BNaFeY-glasses. Moreover, the transmittance of the sample with the highest Y₂O₃ content is about 93 % within the visible range. Because of the diluted Fe content within BNaFeY-glasses, the five absorption bands of Fe are not observed. So, these bands are detected by magnifying the spectra within the visible region. These bands are labeled ?₁, ?₂, ?₃, ?₄ and ?₅ at wavelengths 454.5, 518.4, 652.5, 707 and 808 nm respectively. These bands were used to calculate the crystal field splitting (10Dq) for all BNaFeY-glasses. The outstanding 10Dq increment with further Y₂O₃ doping was explained in terms of more interactions between Fe cations and their surroundings. On the other side, the shielding parameters were considered to examine the competence of these transparent glasses against nuclear radiation. We found that the sample doped with the highest amount of Y₂O₃ has the highest linear attenuation coefficient and the lowest half-value layer (HVL). From the HVL results, we need a thickness of 3.646 cm from the sample with 5 mol% of Y₂O₃ to get protection from 50% of the photons with energy of 0.662 MeV, and this thickness is increased to 5.137 cm when the energy is 1.333 MeV.     

Novel gallate-based oxide and oxyfluoride glasses with wide transparency,high refractive indices,and low dispersions

The glass-forming region of a BaO-La₂O₃-Ga₂O₃ ternary system was confirmed and BaF₂-BaO-La₂O₃-Ga₂O₃ new oxyfluoride glasses were prepared by a containerless processing. We also analyzed the physical, thermal, and optical properties of new oxide and oxyfluoride glasses. The direct effects of the substitution of oxygen by fluorine and the effect of BaO and La₂O₃ on the refractive index and Abbe number were discussed on the basis of electronic polarizability and resonance wavelength of oscillator. The refractive indices increased with increasing La₂O₃ concentration because La₂O₃ increased the electronic polarizabilities. Abbe number increased with increasing BaO and fluorine concentration because of the decrease in resonance wavelength of oscillator. By the combination of the BaO, La₂O₃, and fluorine in the gallate glass system, we could obtain novel oxide and oxyfluoride glasses with high refractive index (1.81-1.95) and high Abbe number (31-55). The absorption edge in UV region shifted to the shorter wavelength and IR cut-off wavelength shifted to the longer wavelength with increasing fluorine. Therefore, wide transparent glass was obtained from 262 nm to 11.3 μm.     

Enhancing the electrical conductivity of vanadate glass system (Fe2O3, B2O3, V2O5) via doping with sodium or strontium cations

Novel glass-ceramics of the nominal molar compositions 20Fe₂O₃·20B₂O₃·(60-x)V₂O₅· (xNa₂O or xSrO) (where x?=?0 or 10) were prepared by traditional melt technique. Differential thermal analysis (DTA) was implemented to study the thermal behavior of the prepared glasses. Vanadium pentoxide (V₂O₅), iron vanadate (FeVO₄), sodium vanadate (Na₃VO₄) and strontium vanadate (with different formulae) were crystallized and identified by X-ray diffraction (XRD) analysis under certain conditions of heat-treatment. Further characterization of glass and glass ceramics samples were performed using scanning electron microscope (SEM), density, electrical and dielectric measurements. In conclusion, our study elucidated that the substitution of vanadium by Na⁺ and Sr²⁺ ions enhanced the conductivity at 180?°C from 5.11?×?10^?4 for unmodified glass to 2.93?×?10^?3 and 1.03?×?10^?2?S?cm^?1 for Na- and Sr-modified glasses.     

Optical properties,thermal stability,and forming region of high refractive index La2O3–TiO2–Nb2O5 glasses

The high refractive index La₂O₃–TiO₂–Nb₂O₅ glasses were prepared by containerless processing, and the glass‐forming region was determined. The refractive index showed the range from 2.20 to 2.32, and the values were much higher than those of most optical glasses. The completely miscible 30LaO_3/2–(70?x)TiO₂–xNbO_5/2 (0 ≤ x ≤70) system was fabricated to study the compositional dependence of refractive index and optical transmittance. The crucial determinants of the refractive index of oxide glasses, oxygen molar volume, and electronic polarizability of oxygen ions were calculated. The principle of additivity of glass properties was suitable for the calculation of refractive index between glass and compositional oxides. All the glasses were colorless and transparent in the visible to 6.5 μm middle infrared (MIR) region. These results are useful for designing new optical glasses with high refractive index and low wavelength dispersion in wide optical window.     

Influence of La2O3 on the structural,mechanical and optical features of cobalt doped heavy metal borate glasses

The impact of rare-earth oxide (La₂O₃) on the structural, mechanical and optical properties of cobalt-doped heavy metal borate glassy system is studied. XRD assured the amorphous nature of the prepared samples. The density and average boron-boron separation were found to increase with La₂O₃ content, thereby enforcing the compactness of the glass network. FT-IR analysis revealed the growth of NBO's ratio due to the gradual conversion of the tetrahedral (BO₄) to trigonal (BO₃) units with the development of a certain boroxol group (B₃O₆) fraction. A noticeable enhancement of the elasticity properties, such as the elastic, bulk, and Young's moduli, as well as the microhardness, was confirmed by measuring the ultrasound velocities within prepared samples. The absorption and photoluminescence emission spectra showed a progressive enhancement of Co³⁺/Co²⁺ ions in the tetrahedral and/or octahedral positions with La₂O₃ content. The ligand field strength and Racah parameters were estimated, in which the ionicity nature between Co²⁺ ions and the nearby ligands is inferred from the nephelauxetic effect. Absorption edge analysis, here performed through Tauc's model, showed a decrease in the band gap and a rise in Urbach energy; the values of each, together with the metallization parameter, reflect the semiconducting character of the prepared samples. The dispersion of the refractive index was determined using the Wemple-DiDomenico single oscillator model and compared to the optical gap energy. Additionally, the nonlinear optical coefficients, here determined within the lower energy spectral range using a third-order nonlinear susceptibility, exhibited progressively increasing value, suggesting a possible integration of the current system in potential nonlinear optical applications. Furthermore, the absorption and photoluminescence spectral tunability here offered through La₂O₃ additives qualifies the current glasses as optically active materials for many possible applications in multifunctional optical devices operating in visible and near-infrared spectral regimes.